Recently, a two-dimensional scanning projector which enlarges and projects, on a scanned surface such as a screen, an image generated by causing a light beam emitted from a light source to scan in two dimensions is known. Furthermore, regarding a two-dimensional scanning projector, a device configured such that an optical axis of a scanning optical system is inclined with respect to the screen is known. The two-dimensional scanning projector configured as described above projects an image to the entire screen from an image generation unit arranged under the screen. Thus the configured two-dimensional scanning projector enables so-called shooting-up projection (which is also called tilting projection and means “projection where a light ray proceeding to the center of the screen is tilted with respect to the screen”) in which an image is projected to the entire screen from an image generation unit arranged under the screen. The device capable of performing shooting-up projection is able to achieve space-saving in comparison with a conventional non-shooting-up type projector in which an optical axis of a scanning optical system is substantially orthogonal to the screen.
However, there is a problem that the image projected by the device capable of performing the shooting-up projection has larger TV distortion and trapezoidal distortion relative to the image projected by the non-shooting-up type projector. The TV distortion as used herein means a distortion of an image projected on the screen. Specifically, the TV distortion is represented by a numeric value of a distortion of the longer of a projected image to the shorter side of the projected image. For example, Japanese Patent Provisional Publication No. 2004-138719A discloses a technique for reducing the TV distortion in a projector.
The publication 2004-138719A discloses a two-dimensional scanning projector in which a scanning optical system is arranged between a light source and a screen. In the projector, the scanning optical system is arranged to be decentered. With this configuration, a designer of the projector tries to correct the TV distortion and etc. by giving an anamorphic effect to a projecting optical system.
However, since the projector described in the publication 2004-138719A is configured such that the scanning optical system is decentered, the configuration of the projector becomes inevitably complicated. In addition, positioning of lenses with a high degree of accuracy is required.